Track your monthly data usage and guard against exorbitant overage fees. Tell the app how many gigs your phone plan allows and it creates an icon in your notification bar that changes color as you approach your limit. Green = cool; red = danger.
WIRED Set a notification to alert you when you've hit a certain percentage of your quota. View usage trends today, by week, and by month.
TIRED Only the pro version ($3.17) reports how much data individual apps are using.